Preparation of diamond dies for wire drawing



Patented Sept. 18, 1945 PREPARATION OF DIAMOND DIES FOR WIRE DRAWING Alan Edgar Jones, Prescot, England, assignor to British Insulated Cables Limited, Prescot, England, a British company No Drawing. Application April 21, 1945, Serial No. 589,704. In Great Britain May 18, 1944 2 Claims.

The preparation of diamond dies for use in wire drawing includes the steps ofdrilling the hole, shaping the drilled hole and finishin it to the exact size required. Each of these steps is performed by producing relative rotation between carrier.

ends.

each case.

th order of 1 mil per hour.

later stages.

hexanol it is much easier than with the other carriers mentioned to clean the surface of the diamond, or of the wire or the needle when this is required to be done.

The action of the carrier is not fully under- It is found that small additional 5 the diamond and a needle or wire, generally stood, but it is suggested that when using olive accompanied by a slow or intermittent endwise oil or lanoline as a carrier there is a lubricating reciprocation. Diamond powder is utilised as the condition in addition to the carrying action due cutting agent, working between the needle or to the presence of a cushion between the diawire and the diamond. The powder is applied mond particles and the wall of the hole which by using a liquid or semi-liquid material as a retards the rate of cutting; whereas when using cyclohexanol the desired carrying action is ob- For the drilling operation a steel needle is used tained without lubrication as compared with the with one end working in the hole formed in the other materials mentioned and the absence of the diamond. A mixture of fine diamond powder i5 cushion permits the sharp cutting edges of the with a carrier, for instance olive oil or lanoline, diamond powder particles to have free access to is fed from a small scoop or palette on to the the wall of the hole. It is further suggested that needle in the hole. For the other operations the in drilling there is movement of the diamond needle or wire passes through the hole and may particles within the body of the carrier liquid be parallel with the axis of the hole or inclined away from the base of the hole where the needle thereto. When a wire is used it is held at both operates, and that advantageous action is ob- The feeding of the diamond powder is tained by the rapid and regular replacement of carried out in substantially the same manner in these particles by others suspended in the car- Each process is a slow one, for inrier, and that this occurs more effectively when stance in drilling stones of a certain weight and the carrier is cyclohexanol, than with the previsize of die hole the rate of piercing may be of ously known carrier materials. Again, where the movement of the cut-ting particles away from the By the present invention the process is imbase of the hole is rendered slow by the retardproved by using as-a carrier the liquid cycloing effect of viscosity in the carrier, as with hexanol. In this improved process the speed or liquids such as olive oil, a condition is created in removal of material in the hole is greatly inwhich the broken down particles of diamonds creased. For instance, in drilling operations in cause a burnishing rather than a cutting action comparable conditions the average rate of piercto take place on the surfaces of the hole, resulting when usin olive oil or lanoline as the caring in the production of a flat polished base to rier was 1 mil per hour, whereas when using cyclothe hole which is resistive of further penetraheXanol the rate increased to 8 mils per hour. tion. This provides a possible explanation of the In the shaping operation the rate of increase of reduction in frequency of regrinding necessary diameter of the die channel was increased from when using cyclohexanol, since the increased re- 0.25 mil per hour for olive oil or lanoline to 3.0 sistance to penetration is productive of an inmils per hour for cyclohexanol. In addition to 40 creased rate of wear of the needle point. these improvements a smoother surface and a The oyclohexanol is mixed with the diamond better shape in the hole is obtained, so that less powder and the mixture applied to the wire or work has to be done in the final operations. It the needle. will be understood that from time to time it is quantities of cyclohexanol must generally be addn ss y to re the shape of the point of ed from time to time to make up for the occurthe needle: this is required to be done less frerence of a small loss of the liquid. This is done fl ently when using cyclohexanol. When using by feeding with a small brush on to the wire or olive oil as the carrier in certain conditions when th needle i the hole. This loss may be due drilling, stoppage for regrinding is necessary at in part to evaporation (although this is small in intervals as short as 10 minutes. In the same any case), or it may be due to the throwing out conditions when using cyclohexanol the interval of the liquid from the hole by centrifugal force time is increased to 30 or 40 minutes in the early or to the need for thinning down the mixture. stages of a drilling and up to minutes in the Good proportions for the mixture are about five parts of cyclohexanol to one part of diamond There is the further advantage that with cyclo- 6 powder by volume. The ratio may be varied to some small extent depending upon the work being done. For instance, in the early stage of drilling, when a, large surface area of needle point is in use, the dispersion may be more concentrated i. e. may contain a larger proportion of diamond powder; in the later stage when there is a reduced surface area of needle point in use the dispersion may be less concentrated.

If a substantial part of the relative rotation is obtained by the movement of the die an enclosing'cap is necessary or advisable to prevent excessive loss of liquid'from the hole. A machine working with the axis of rotation vertical, or approximately vertical, gives superior results as compared with a machine in which the axis of rotation is horizontal.

For the final operations it may be advantageous to resort to the use or olive oil or ianoline as a carrier to obtain the smaller rate of removal of material as the final dimensions are being arrived at.

What I claim as my invention isr 1. In the process of preparing a hole in 8; diamond die for wire drawing, using as the operating member a needle or wire moved relative to the diamond, the stepof feeding the space be- IO tween the operating member and the surface of the hole with diamond powder suspended in cyclohexanol.

2. A cutting agent for use in preparing holes in diamond dies consisting of a suspension of It diamond powder in cyclohexanol.

ALAN EDGAR JONES. 

